1. Field of the Invention
The present invention relates to a disk drive having a breathing filter protecting mechanism.
2. Description of the Related Art
In recent years, a magnetic disk drive as a kind of external storage for a computer has been increasingly reduced in size, particularly in thickness, and low power consumption has been required. On the other hand, increasing the recording density of a magnetic disk to increase the capacity has also been required, and the number of magnetic disks to be mounted in a magnetic disk drive is increasing.
In a magnetic disk drive for a computer, a contact start and stop (CSS) system is generally adopted as the relationship between a head and a magnetic disk. This system is such that while the disk is in rotation, the head is kept flying a slight distance away from the disk at a microscopic height owing to the balance between a flying force applied to the head by an air flow generated by high-speed rotation of the disk and an elastic force of a suspension pressing the head onto the disk. When the disk rotation is stopped, the head is moved to a contact zone formed on the disk and comes into contact with the disk at the contact zone. While the disk is at rest, the head and the disk are kept in contact with each other.
As mentioned above, the head is kept flying above the disk at a microscopic height during rotation of the disk. Accordingly, there is the possibility of a head crash or the like due to even a small amount of dust or the like amount. To cope with this problem, the magnetic disk and the magnetic head for reading/writing data on the magnetic disk are enclosed in a sealed chamber defined as a disk enclosure (housing). However, it is difficult to keep the sealed condition in the magnetic disk drive over a long term. Further, the flying height of the magnetic head may change with pressure changes in the sealed chamber due to temperature changes or the like.
To prevent this problem, a small breathing hole (ventilation hole) is formed through a cover forming a component of the housing of the magnetic disk drive, thereby making the inside pressure of the magnetic disk drive substantially equal to the outside atmospheric pressure. The small breathing hole is usually provided with a breathing filter to prevent the entry of dust present in the atmosphere into the magnetic disk drive while making the inside pressure of the magnetic disk drive substantially equal to the outside atmospheric pressure.
The breathing filter used in the conventional magnetic disk drive is formed of nonwoven fabric, or the like, and is designed only for the function of passing air to keep the inside pressure of the magnetic disk drive substantially equal to the outside atmospheric pressure and for the function of not passing dust present in the atmospheric air. Since the breathing filter is formed of nonwoven fabric or the like, there is a possibility that an insect, such as an ant may break the breathing filter and enter the magnetic disk drive, which would cause problems.